CVE-2025-40124

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue was identified in the Linux kernel related to inaccurate exception reporting within the copy from user and copy to user functions for UltraSPARC III architectures. A bug in exception handlers, introduced with new user-space memory reference handling, caused incorrect return values when exceptions occurred during bulk copy operations. Specifically, the masking of registers was performed after the bulk copy loop instead of before, leading to inaccurate calculations of remaining bytes to copy. This issue stemmed from a BUG ON condition in ext4 code with large folios enabled, triggered by copy from user returning impossibly large values. The functions copy from user and copy to user are affected.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.